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Residence Power Meter And Reactive Loads Question ?

Discussion in 'Electrical Engineering' started by Bob, Dec 24, 2009.

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  1. You have Power and VA mixed up. If you said the same VA will yield
    LESS metered reporting, you would be right. That's because as the
    current drifts further out of phase (and assuming the current amplitude
    remains constant), the Power drops. This is because the meter is
    measuring Power (or more correctly, the integral of Power, Energy).

    Alternatively, if you want the Power consumption to remain the same
    as you shift the current further out of phase, the current (and VA)
    will increase to compensate. Regardless, the meter measures the
    [integral of] Power, and will spin at the same rate for constant
    power consumption regardless of phase angle. If you want to try this
    second case for yourself, play with the first java applet example
    (Phase Shift) on http://www.cucumber.demon.co.uk/PowerFactor/
    which shows how the various parameters such as current and VA change
    as you change the phase shift, whilst drawing constant power.
     
  2. krw

    krw Guest

    Now go back and read what you snipped, AlwaysWrong. It's in there.
    You don't read, AlwaysWrong. Did I say that you're always wrong?
    You don't read well, AlwaysWrong. Try again, if you can keep you
    blood pressure below 300. If not, just take a week off and relax. A
    month would be better.
    Nice rant, AlwaysWrong, but you're still always wrong.
     
  3. krw

    krw Guest

    No one said anything different, DimBulb.
    Yes, but the inductive load doesn't dissipate the same power as the
    resistive load, now does it AlwaysWrong? The torque is PROPORTIONAL
    to the *real* power of the load. There is no error for an inductive
    (or capacitive) load.
    Because the power in the inductive load is *LOWER*, AlwaysWrong.
    No, ALwaysWrong, the capacitors are there to correct their VARS so
    they aren't supplying current that isn't used, with the losses that
    entails. The capacitors don't affect the meter _at_all_. They
    *can't*, they're before the meter.
    AlwaysWrong, is always wrong.
    You never went to school, DimBulb.
     
  4. What do you think "nor is the torque applied" refers to, you fucking
    retard?

    Whenever ANY shaft is made to rotate by ANY force, the force acting on
    the shaft is torque.

    I do not expect you to get it, though, K-Tard.
     
  5. krw

    krw Guest

    You really are retarded, DimBulb. Of course a torque is applied to
    the disk. The point is that the torque is proportional to the *REAL*
    power, not VA.
    You clearly don't get any physics, DimBulb. You're AlwaysWrong about
    everything else, too. No surprises for any here, though.
     
  6. Guest

    Guest Guest

    ------
    Torque has been applied to the shaft- true- the torque itself is not
    applying a torque- which is due to the interaction of fields produced by
    both the stator and the rotor part of the motor- classical electromagnetic
    energy conversion concepts apply (as taught at the junior levels of EE).
    ------------
    Again, as others, such as Gabriel, whom I respect, have pointed out, and as
    you would find out for yourself if you cared to do a little bit of research
    , you are wrong. The meter inherently reads real power- not volts*amperes.
    So, if you have a resistive load drawing 10A at 100V rms, the power will be
    1000Watts and if you have a reactive load , inductive or capacitive at 0.8
    pf at the same voltage and current magnitude, the real power will be 800
    watts. So, the KWH meter will run slower in the latter case because the
    real power component is lower. The meter is designed to measure the real
    power (actually energy) even if the load is inductive or capacitive. It does
    mechanically what an electronic meter does by multiplying and averaging
    sampled data. This has been beaten to death in an earlier thread.
    -----
    ----------
    It is amazing in that in the short sentence above, there are several
    incorrect concepts. Tell me, how the meter "down stream" of the capacitors
    will be more accurate due to the capacitors. The meter sees the load
    "downstream" from itself and even if it's accuracy is affected by the
    inductance of the load (and it isn't), the capacitance will not change this
    because the corrective effect of the capacitance is only seen "upstream" of
    the capacitors. Kirchoff reigns!
    If the ideas that you present are based on what you learned in "school" ,
    you have a good case for suing your teachers for misleading you.
    Do you want my CV ( or some reference textual material ( I don't have much
    at the "basic" level, but have some at the junior to graduate level in my
    back closet)?

    I'm not bluffing.
     
  7. Guest

    Guest Guest

    -------------------------------------
    Vembu Gourishankar & Donald H. Kelly "Electromechanical Energy Conversion"
    Second edition, Intext, 1973.

    It appears that I have a somewhat deeper knowledge than you have
    suggested---and I don't substitute invective for rational thought.

    happy new year!
     

  8. Pretty hard since "torque" is not a "thing".

    Got any more silly horseshit?
     

  9. These meters are NOT a typical motor, dumbass.

    There is no "rotor" other than the Al disc, and it exhibits NO field.
    It responds to the field around it. Period.
     

  10. If your previous remark was true, sure. But it was not a true remark.
    There is no "rotor", and there is no coil or magnet on the part that a
    dope like you would call the rotor.

    The Aluminum is what responds to the field. That is why this "motor"
    type will never be seen as a mechanical power source. The torque applied
    by the field is enough to turn it, and the gear resistance, but there is
    no way one could perform any real "work" with such a "motor".

    It, in fact, can be argued as being incorrectly termed as a motor.
     

  11. It is mechanical. It does not perform ANY "sampling of data".

    It responds ONLY to the resultant force applied to it.

    That force is less for an out of phase reading, despite the power
    (energy) being the same. RESULTANT FORCE.

    So, even if we use your term "sample", the "sample" is what ends up
    doing less turning for the same amount of use. Why? The resultant force
    applied to this type of meter has an inherent error which is due to its
    physical construction that you are apparently unable to grasp and were
    obviously never educated about. It is physical. There is nothing you can
    do about it with words. Hell, you cannot even grasp how capacitance
    upstream side can play into how such a meter reads. It is all one big
    circuit, dude. So it doesn't matter where they are located, they play
    into the operation of the reactive device, as well as that type of
    meter's accuracy when reading such a live circuit.
     
  12. The meter sees the load in the circuit loop it is in. It is a circuit.
    Upstream or downstream doesn't matter.
     
  13. My point exactly.
     

  14. Like I give a fat flying **** what you did. I was making the point
    that whatever it was, you missed something. Doh!
     

  15. No. You make stupid remarks like "no torque is applied", when the topic
    is about the turning of a shaft. It doesn't get much more stupid than
    that.

    I would say that despite you publishing a book, you definitely missed a
    few things along the way.
     
  16. krw

    krw Guest

    AlwaysWrong once again (and again, and again, and...) proves the
    validity of his given name.
     
  17. krw

    krw Guest

    Don, consider yourself among the elite! You scored a DimBulb *seven*
    bagger! That's the best I've ever done and I've been correcting
    AlwaysWrong's, always wrong, crap for years! Way to go!
     

  18. You're a fucking retard.

    The best thing your'll ever do is feed worms.
     
  19. krw

    krw Guest

    Why thank you, AlwaysWrong. Since you're *always* wrong...
    AlwaysWrong, that'll be your only contribution to the world, but
    you'll somehow get that wrong too, as always.
     
  20. Guest

    Guest Guest

    ---------
    Wrong:
    the rotor has eddy currents which produce a field interacting with the
    "stator field" to produce torque. Essentially it is a form of induction
    motor and can be analyzed as such.
    _----------------
    Wrong again- according to your concept the drag cup motor won't work because
    it doesn't have a coil or magnet. The fact that the "stator windings" are
    set up to produce a rotating field and the aluminum disc is conductive, is
    sufficient. I have made demo motors with beer cans or paper clips as
    rotors- anything conductive works.
    Is it a good design for a mechanical power source? No. but it does provide
    motor action.

    ---------------
    ------
    , You have a reading problem. The electronic meter multiplies and averages
    sampled data. The mechanical meter multiplies and averages instantaneous
    values of power achieving the same result.
    ---------------
    ---------
    Let's see, the circuit as a whole does affect the load voltage and current-
    that is true. Changes in the load will be affect the circuit as a whole-
    also true. However, the meter measures the voltage across the load and the
    current through the load, whatever they may be. Accordingly the meter will
    measure the power delivered to the load and at any given load impedance and
    voltage, it cannot tell the difference between the situation of an ideal
    source connected above it or a long line connected to a grid system with or
    without capacitances. If a capacitor is connected on the load side of the
    meter, it will change the current and voltage at the metering point and the
    meter will measure accordingly- but as the capacitance only compensates for
    inductive reactive VAR's , it will not correct the meter and the only effect
    it will have on the meter will be a change in losses in the wiring on the
    load side of the meter.
    An industry may put capacitors downstream of the meter in order to improve
    power factor- not because of any attempt to correct the meter but to reduce
    the peak KVA demand which is not registered by a KWH meter but is reflected
    in demand metering charges.
    A utility putting a capacitor upstream of the metering point (and it is
    always a parallel capacitor for very good reasons) doesn't correct the meter
    downstream because it only modifies the upstream current (KCL applies). Do
    you want some circuit analysis of this?
    ----------------
    ----
    So, are you saying that, if the meter is moved to a different location in
    the circuit, it reads the same thing? If not, then what are you implying?
    Have you ever used a wattmeter in a circuit?

    I don't know where you got your circuit or motor concepts but somewhere,
    somehow, something is badly amiss in your understanding. There are many
    references out there Shaum's outline on circuits is quite good for circuits
    and a sophomore text such as Basic Electrical Engineering by Fitzgerald,
    Higginbotham etc has been resurrected many times in different editions.
    Also try:
    http://fourier.eng.hmc.edu/e84/lectures/ch3/node1.html

    http://nptel.iitm.ac.in/courses/Web... Technology/pdf/L-44(GDR)(ET) ((EE)NPTEL).pdf

    considers the interaction between the eddy currents and the flux of the
    stator- in general, this interaction is actually better described in terms
    of the interaction between the stator flux and the flux produced by the eddy
    currents. In any case it is simply a form of shaded pole induction motor.

    If you wish to give some tangible circuit models to present your points for
    discussion- please feel free to do so. If you wish me to give some examples,
    let me know.
     
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